package com.easyj.admin.configuration;

import java.io.IOException;

import org.apache.commons.lang3.StringUtils;

import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.deser.std.StdScalarDeserializer;
import com.fasterxml.jackson.databind.jsontype.TypeDeserializer;

/**
 * 复制 com.fasterxml.jackson.databind.deser.std.StringDeserializer 并修改;
 * 空字符串转为 null 并对字符串 trim()
 * 
 * @author hjf
 *
 */
public class StringBlanktoNullDeserializer extends StdScalarDeserializer<String> // non-final since 2.9
{
    private static final long serialVersionUID = 1L;

    

    public StringBlanktoNullDeserializer(boolean toNull)
    {
    	super(String.class);
    	this.toNull=toNull;
    }

    private boolean toNull;
    // since 2.6, slightly faster lookups for this very common type
    @Override
    public boolean isCachable() { return true; }

    @Override // since 2.9
    public Object getEmptyValue(DeserializationContext ctxt) throws JsonMappingException {
        return "";
    }

    @Override
    public String deserialize(JsonParser p, DeserializationContext ctxt) throws IOException
    {
        if (p.hasToken(JsonToken.VALUE_STRING)) {
        	if(!toNull) {
        	return p.getText().trim();
        	}
        	else {
	        	String v=p.getText();  //增加对空字符串处理，和trim()
	        	if(StringUtils.isBlank(v)) {
	        		return null;
	        	}else {
	        		return v.trim();
	        	}
        	}	
        }
        JsonToken t = p.getCurrentToken();
        // [databind#381]
        if (t == JsonToken.START_ARRAY) {
            return _deserializeFromArray(p, ctxt);
        }
        // need to gracefully handle byte[] data, as base64
        if (t == JsonToken.VALUE_EMBEDDED_OBJECT) {
            Object ob = p.getEmbeddedObject();
            if (ob == null) {
                return null;
            }
            if (ob instanceof byte[]) {
                return ctxt.getBase64Variant().encode((byte[]) ob, false);
            }
            // otherwise, try conversion using toString()...
            return ob.toString();
        }
        // allow coercions for other scalar types
        // 17-Jan-2018, tatu: Related to [databind#1853] avoid FIELD_NAME by ensuring it's
        //   "real" scalar
        if (t.isScalarValue()) {
            String text = p.getValueAsString();
            if (text != null) {
                return text;
            }
        }
        return (String) ctxt.handleUnexpectedToken(_valueClass, p);
    }

    // Since we can never have type info ("natural type"; String, Boolean, Integer, Double):
    // (is it an error to even call this version?)
    @Override
    public String deserializeWithType(JsonParser p, DeserializationContext ctxt,
            TypeDeserializer typeDeserializer) throws IOException {
        return deserialize(p, ctxt);
    }
}
